24-12-2016, 02:06 PM
(This post was last modified: 24-12-2016, 02:16 PM by Mike Watterson.)
Horizontal is better for longer distance / fringe coverage over the horizon, at higher frequencies the over the (optical) horizon shortens and thus horizontal is less important.
Vertical (or circular) is better for mobile.
Circular has a half power penalty unless you have circular reception of the same handedness, (1/4 distance at same power) but works equally with horizontal or vertical polarised aerials.
Still, today, long distance SSB or digital mode Amateur radio with larger aerials is always horizontal, 144 MHz, 430MHz and 1.2GHz bands. Higher bands tend to use dishes and might use both polarisations (on separate channels) for full duplex). Amateur Satellite, C band and Ka band often is Circular polarisation (in some cases because satellite is rotating, or weather rotates the signal. Most Ku band satellite uses horizontal and vertical on alternate channels, which thus can overlap slightly. Same may be true on Ka, except the handedness of circular is reversed.
Mobile Amateur is always vertical.
I've no idea why the useless negative gain halo aerials are still sold for Band II FM as no Band II has been horizontal only for years.
On Band III and UHF, Horizontal and Vertical is used on TV (still) to provide extra isolation on co-channels. Due to greed, European regulators, cheered on by FCC and Ofcom are taking away 700MHz to Mobile.
It dooms TV to having no space for fill in for Mobile use, 3D or 4K services or innovation. But Ofcom and Comreg already stated they want to abolish Terrestrial TV altogether.
700 and to a lesser extent 800 are too low a frequency for decent mobile capacity as cell size is poorly controlled and too large.
The latest 4G spec (and regulators) allow the Mobile companies to use 4G channnels in pure broadcast mode to deliver Pay TV. Internet TV (esp. Mobile) isn't scaleable. Cable and Satellite are complementary to Terrestrial, not a replacement, but then Regulators are only interested in subscription / pay services as they can charge more for spectrum licences.
You see why 700 & 800 is being sold to Mobile? Not for better Mobile. But to save costs and make government revenue. New coverage claims for so called 5G say nothing much about performance. More smaller cells costs more but gives more speed and lower power at mast, and lower power (x4 battery life) in handset.
The 900, 1800, 2100 are underutilized. The 2500 will be underutilised too.
It's greed and madness.
So is so called "White Space".
Vertical (or circular) is better for mobile.
Circular has a half power penalty unless you have circular reception of the same handedness, (1/4 distance at same power) but works equally with horizontal or vertical polarised aerials.
Still, today, long distance SSB or digital mode Amateur radio with larger aerials is always horizontal, 144 MHz, 430MHz and 1.2GHz bands. Higher bands tend to use dishes and might use both polarisations (on separate channels) for full duplex). Amateur Satellite, C band and Ka band often is Circular polarisation (in some cases because satellite is rotating, or weather rotates the signal. Most Ku band satellite uses horizontal and vertical on alternate channels, which thus can overlap slightly. Same may be true on Ka, except the handedness of circular is reversed.
Mobile Amateur is always vertical.
I've no idea why the useless negative gain halo aerials are still sold for Band II FM as no Band II has been horizontal only for years.
On Band III and UHF, Horizontal and Vertical is used on TV (still) to provide extra isolation on co-channels. Due to greed, European regulators, cheered on by FCC and Ofcom are taking away 700MHz to Mobile.
It dooms TV to having no space for fill in for Mobile use, 3D or 4K services or innovation. But Ofcom and Comreg already stated they want to abolish Terrestrial TV altogether.
700 and to a lesser extent 800 are too low a frequency for decent mobile capacity as cell size is poorly controlled and too large.
The latest 4G spec (and regulators) allow the Mobile companies to use 4G channnels in pure broadcast mode to deliver Pay TV. Internet TV (esp. Mobile) isn't scaleable. Cable and Satellite are complementary to Terrestrial, not a replacement, but then Regulators are only interested in subscription / pay services as they can charge more for spectrum licences.
You see why 700 & 800 is being sold to Mobile? Not for better Mobile. But to save costs and make government revenue. New coverage claims for so called 5G say nothing much about performance. More smaller cells costs more but gives more speed and lower power at mast, and lower power (x4 battery life) in handset.
The 900, 1800, 2100 are underutilized. The 2500 will be underutilised too.
It's greed and madness.
So is so called "White Space".
